Ku-Band 32-Channel 1D Active Phased Array: Aperture Architecture, Transmit Power, and Monopulse Integration

In radar and directional tracking systems, a 1D active phased array provides electronic elevation steering while maintaining a fixed, non-scanning azimuth aperture. Integrating a specialized Ku-band 32-channel phased array antenna combines an active 32-channel transmit/receive (T/R) network with a 32 × 32 planar radiating aperture operating from 15.8 GHz to 16.8 GHz, delivering high system Equivalent Isotropically Radiated Power (EIRP) within defined power-consumption and operating-temperature limits.

Why 32 Channels for a 1,024-Unit Aperture?

The relationship between active channel count and radiating element count is a key architectural distinction in this front-end. The 32-channel count refers to the active T/R module network, while the 1,024-unit figure describes the total planar radiating aperture; these two quantities represent different architectural layers of the array.

The planar aperture is configured as an Nx = 32 (azimuth) by Ny = 32 (pitch/elevation) matrix, comprising 1,024 radiating units. The 32-channel active T/R network provides the active architecture for 1D electronic elevation scanning across this aperture, supporting one-dimensional electronic beam steering while maintaining a directive physical aperture.

How the 1D Architecture Delivers ±40° Elevation Scanning

For the 1D scanning configuration, electronic beam control is applied along the elevation axis:

• Pitch Electronic Scanning (±40°): The 1D scanning architecture supports electronic beam steering across a ±40° pitch sector.
• Beam-Pointing Error: The specified typical beam-pointing error is ≤0.3°, supporting precise beam positioning across the specified scan sector.
• Non-Scanning Azimuth Aperture: The azimuthal dimension contains 32 radiating units and remains fixed and non-scanning, providing a directional horizontal aperture suitable for systems that rely on mechanical azimuth rotation or fixed-sector surveillance.

From RF Excitation to System EIRP: Transmit Path and Power Performance

The transmit path is specified for an RF excitation input of 18 dBm ± 1.5 dBm and system operation across 15.8–16.8 GHz:

• RF Drive and Distribution: The front-end accepts an input RF excitation of 18 dBm ± 1.5 dBm. An internal drive amplification module amplifies this signal before the power divider distributes the RF drive to the 32 active T/R channels.
• Single-Channel Power: Each active channel delivers a peak output power of ≥27 dBm across the operating band.
• System EIRP: The system provides a normal EIRP of ≥82 dBm at room temperature.
• Pulsed Duty Operation: The front-end supports transmit duty cycles of up to 25%, with total DC power consumption rated at ≤200 W under maximum duty operation.

Why the Receiver Integrates Sum and Difference Processing

For target tracking and monopulse angle estimation, the front-end incorporates integrated sum (Σ) and difference (Δ) signal processing within the RF assembly:

• Receive Amplification and Compensation: Incident electromagnetic signals captured by the aperture undergo amplification and phase/amplitude compensation across the receive channels.
• Monopulse Differential Network: The conditioned signals enter an integrated differential network that outputs simultaneous sum (Σ) and difference (Δ) signals. This allows downstream radar processors to derive monopulse angle information for elevation tracking.
• G/T & Reception Gain: The receiver path achieves a weighted gain-to-noise-temperature ratio (G/T) of ≥2.5 dB/K at room temperature, alongside a total reception gain of ≥55 dB across the 15.8–16.8 GHz band.
• Polarization: The antenna utilizes vertical polarization as its typical operational configuration.

Power, Mechanical, and Interface Integration

The active Ku-band front-end is packaged as a compact integrated assembly with defined mechanical and electrical boundaries:

• DC Power Input: The subsystem operates over a DC input range of 18 V to 36 V, drawing ≤200 W at a 25% transmitting duty cycle via a dedicated J30V2_9TJL power connector.
• Enclosure and Mass: The unit measures 420 mm × 400 mm × 62 mm and weighs ≤9 kg (excluding separate frequency conversion and signal processing units).
• Operating Temperatures: The assembly is specified for an operating temperature range of -40 °C to +60 °C, with non-operating storage ratings from -50 °C to +70 °C.
• Thermal Integration: System-level thermal design should account for the specified power consumption of ≤200 W at a 25% transmit duty cycle to maintain the assembly within its -40 °C to +60 °C operational limit.
• Surface Treatment: The metal cavity features a natural-conducting oxide coating, while the external antenna face is finished with a white primer.
• Signal Interfaces: SSMP-J connectors provide the coaxial Ku-band RF interface, while a multi-pin J30J_15TJL connector carries serial-port data, clock, and synchronization signals for system control and status reporting.

Frequently Asked Questions (Phased Array Architecture & Transmit)

Q: Why use a 32-channel architecture for a 1,024-unit aperture?

A: The architecture uses 32 active T/R channels rather than one independently controlled T/R channel per radiating unit across the 32 × 32 aperture (1,024 units). This provides 1D elevation scanning over the specified ±40° pitch sector while potentially simplifying the associated RF, control, and power architecture.

Q: What is the significance of the 18 dBm ± 1.5 dBm input excitation specification?

A: The 18 dBm ± 1.5 dBm input excitation is the specified RF drive condition associated with the stated single-channel output power of ≥27 dBm.

Q: What thermal considerations apply when operating at a 25% transmit duty cycle?

A: At a transmitting duty cycle of up to 25%, maximum system power consumption is ≤200 W. System integrators should account for this power consumption and provide appropriate thermal integration to maintain the assembly within its specified operating temperature range of -40 °C to +60 °C.